1. Technical Field
The present invention relates to a method of and an apparatus for changing colors of an injection molding hot runner die provided with a hot runner which serves as a passage for supplying a melted resin from an injection device to a molding die.
2. Related Art
Heretofore, in an injection machine provided with a hot runner which serves as a passage for supplying a melted resin from an injection device to a molding die, there is known, as a device for changing colors for molding products, a hot runner changing apparatus which comprises a support means for supporting a plurality of hot runners in the state of being placed side by side, a rotation means for rotating a pivotal shaft of the support means, and a fore-and-aft movement means for moving front ends of the hot runners forward and backward (for example, see Japanese patent application publication 5-64828).
Also, there is known an injection molding machine for changing colors for molding products which has two or more plasticizing devices for melting a resin supplied from outside and injecting the melted resin into a molding die. In this injection molding machine, at least one of the plasticizing devices is maintained in an operative position in which it supplies the resin from outside into the molding die while other plasticizing devices are maintained in a stand-by position in which they stand away from the operative position, such that each of the plasticizing devices is capable of switching its position from the stand-by position to the operative position or from the operative position to the stand-by position (see Japanese patent application publication 2001-277283).
However, the hot runner changing apparatus as described in Japanese patent application publication 5-64828 requires the supporting means for supporting the plurality of hot runners in the state of being placed side by side and the rotation means for rotating the pivotal shaft, or the like, so that it becomes complicated in construction and large in scale.
Also, the injection molding machine as described in Japanese patent application publication 2001-277283 requires two or more plasticizing devices thereby incurring an increase in size of equipment.
The present invention is made in view of such disadvantages as seen in the conventional art of injection molding and has its object to provide a method of and an apparatus for changing colors of an injection molding hot runner die which are simple in construction and capable of easily performing a color change for molding products without removing and replacing a hot runner.